Gear set



July 18, 1950 Filed 001;. 30, 1947 W. P. SCHMITTER GEAR SET 3 Sheets-Sheet 1 mvam'oa WALTER P. SCHMlTTER BYMLM A'r'ronnezv July 18, 1950 GEAR SET 3 Sheets-Sheet 2 Filed 001;. 50, 1947 1NVENTOR. WA LTER P.

sCHMlTTER Arromvev Patented July 18, 1950 ES PATENT OF FICE GEAR SET "Walter P; Schmitter, Wauwatosa, Wis assignor to The -Falk= Corporation, Milwaukee, 'Wis., a corporation of Wisconsin Application flctober 30, 1947, Serial No. 782,982

Claims. 1

Thisinvention relates to gear sets. foneiobject of, the present invention is, to provide an improved gear set for driving a pair-of concentric shaftsv in opposite directions.

' The invention maybe utilized toparticular advantage in driving the counter-rotating. propellers of helicopters, airplanes and the like, although other uses are contemplated.

Other more specific objects and advantages will appear-,expressedor implied; fromthe fol lowing description of three illustrative embodiments thereof In the accompanying drawings:

Figure 1 is a longitudinal sectional view of gear set constructed in accordance with the present invention.

Fig. 2 is a fragmentary sectional view of another embodiment of the invention.

Figs. 3 and. 4 are viewssimilar to Fig. 1 of otherembodiments.

' =-'Ihe --gear sets selected for illustration include manyof the advantageous'features disclosed in my copending application Serial N 0. 782,981, and in the copending application of Louis W. Falk, Serial No; '783,009 ,both filed October30, 1947.

The gear set shown in Fig. 1 comprises a ho us-' ing includingseveral separable sections It], I I, I2 and "I3. Two-concentric oppositely rotating shafts 44 and-l 5'projeot from the'forward section ill-of the housing.

" The outer hollow shaft'l4 is journaled in a suitable bearing H5- fixedin the forward housing section 10, and a tubular extension I! at the inner endof shaft 14- is journaled in asleeve-bearing l8 fixed in an appropriate supporting ring 19 .provided within'the housing. shaft [4 is driven by a relatively largeinternal gear 2!! fixed to a disk 2 .carriecl by the shaft.

Shaft extends through the'shaft l4 and is shown-journalediat: its rear end in a suitable bearing' ,22 fixed-in the rear housing section 13. Shaft I 5 is driven by an external gear! 3 keyed orother- Wise fixed thereto.

Thergear 20 is driven by a group of. three equally spaced single helical; :pi-nions 24-;meshing atherowith. Eachpinion 241.18%(351'11661 by. a shaft; 25 iournal d n bearings and Z-Irespect-ively fixed in,- the supporting ring- 19 and ansinwardly projecting web formed within the housing section I I. Each-of the-threeshaf-tsflfi carries algear 29- The inions 30 and? are carried by the adja-' of the several pinions Ell andl l' transmits, an

2 cent ends of separate substantially aligned sleeves 3! and 3| loosely confined between a pair of driving rings 32 and 32' keyed or otherwise. fixed to the opposite ends of a sleeve 33th at loosely .encircles the shaft It and extends looselythrough both of the pinionsleeves 3| and 3i'. Each-of the pinion sleeves is provided with a setof teeth 3 4 or 34' in meshing engagement corre{ sponding teeth formed within one ofthe driving with a gear 35', whose hub extensions 35 are respectively journaled in the web 28 and in a simi-.

lar \vebl l projecting inwardly from thehousing section 12. For this purpose a set of straight spur teeth Mare provided on one end. of thesleeve 33 which mesh with corresponding teeth formed within the hub of gear 35. The gear 35 is driven through an appropriate train of gears 40 and 4| from a laterally offset drive shaft 32. journaledv in suitable extensions 23' and ,31 of the respective webs 23 and. 37.

The helix angle of the gears 29 of oneigroupand of the pinion 30 is equal to but of Opposite hand from that of the otherpinion Si! and gears 29', of the other group, so that the .pinions-30and 3Q automatically assume an axial position such as to equalize the torque load betweenthe two groups of gears 29 and 2t, theiteeth 34-or 34 on .each. pinion sleeve being angularly disposed, each preferably at an angle equal to the helix angle of, the related pinion 30 or 30. Also, each pinion 3t and 36 automaticallyassumes aradial position such as to equalize the .load betweenthe three, gears 29 or 23 of each.. gro,up. Consequently the total torque load transmitted from the gear 35 through the sleeve 33 is equallydivided between the sixgears 29 and 29', and each equal one sixth part of the total torque load transmitted through the-internal, gear, 20.

It will be noted that through the mechanism above described theshaft Mis driven from-the gear35 at a speed greatly below that of gear ,35

and in a direotion opposite to that of the latter. Similar mechanism-is provided fondrivingthe. external gear 23 from the gear .35 and in the.

a shaft 45' having a pinion 44' thereon meshing v with the gear 23. As in the similar gearing herelnabove described, the pinions 59 and function to automatically divide the total torque i load between the six gears 49 and 49, and pinions 44 and 44' ,arepreferably so proportioned as to effect rotation of the gear 23 and shaft 95 at the same rate as the shaft I4 but in reverse direction.

The gear set shown in Fig. 2 is similar in many respects to that shown in Fig. 1 except that the parts are rearranged to permit disposition of the drive shaft in substantial alignment with the driven shafts. The two driven shafts are shown at 54 and 55, shaft 54 being driven by an internal gear 56, and shaft 55 being driven by an external gear 51. The internal gear 55 is driven by six equally spaced pinions 58 meshing therewith and carried by separate shafts 59 journaled in suitable supporting rings 69 and Bi provided within the housing 62.

A group of three single helical gears 53, respectively keyed or otherwise fixed to the rear ends of alternate shafts 59, mesh with a centrally disposed single helical pinion 64. Similarly, each of the remaining shafts 59 carries at 1 its rear end one of a group of three single helical gears 63' which mesh with a second single helical pinion 64', as in the device disclosed in Fig. 1, the helix angle of the pinion 64 being equal to but of opposite hand from that of the pinion 64.

In this instance both pinions B4 and 64' are formed on a single ring 65 which is free to float axially, so that the torque toad transmitted through the ring 65 is equally divided between the two pinions 64 and 54' and equally distributed by them to the two groups of gears with which they mesh. Also, the two pinions 64 and 64' are free to float radially in a manner to automatically divide and distribute between the gears 53 and 63 of each group the torque load transmitted through that pinion 64 and 64' with which the group of gears mesh. It will thus be noted that each of the pinions 58 transmits an equal one sixth part of the entire torque load transmitted to the internal gear 56, all in much the same manner as disclosed in the device of Fig. 1.

Likewise, the external gear 51, carried by the shaft 55, is driven in much the same manner from a pair of single helical pinions 14 and 14' carried by a ring 15, which is also free to float both axially and radially. The helix angles of the pinions 14 and 14' are equal but of opposite hand, and each pinion meshes with a separate group of three equally spaced like gears 73 or 13'. Each of the gears 13 or 13 is keyed or otherwise fixed to a separate shaft 69, which loosely encircles one of the shafts 59 and which is journaled at opposite ends in the supporting rings 60 and 61. A pinion 68 on each of the six shafts 59 meshes with and drives the external gear 51, to thereby drive the shaft 55 in a direction opposite to that of the shaft 54. Again the arrangement is such that the driving pinions 14 and 14 assume axial and radial positions such as to equally divide and distribute the load between the six gears 13 and 13', so that each of the pinions 68 transmits an equal one sixth part of the total load transmitted to the gear 51 and shaft 55.

In this instance both pinion rings 65 and 15 are simultaneously driven from a shaft 16, preferably hollow, which is substantially aligned with the driven shafts 54 and 55. The shaft 16 is shown equipped atits inner end with a ring Tl disposed between the rings 65 and 15 to which it is flexibly connected in driving relation through sets of teeth 18 carried by the ring (1 and meshing with corresponding teeth formed on the pinion rings 65 and 15. The shaft 16 is preferably driven through a flexible coupling 19 of any standard or approved type so as to render the inner end of the shaft l5 free to float in a manner to avoid interference with the desired free floating action of the pinion rings 55 and 15. v

The gear set shown in Fig. 3 also involves two concentric counter-rotating driven shafts B4 and 85. Shaft 84 is hollow and isjournaled in suitable bearings 86 in the forward section. 81 of the housing. Shaft 84 is driven by an internal gear 88 carried thereby. Shaftextends through shaft 84 and is journaled in bearings 89-therein. Shaft 85 is driven by an external gear 9|] carried thereby.

A group of three equally spaced pinions 9| mesh with the internal gear 88; and a similar group of three pinions 9| mesh. with the external gear 90. PinionsSl are carried by the forward ends of separate shafts 92 journaled in fixed bearings 93 within the housing; and pinions 9l' are carriedby similarly mounted shafts 92 individually disposed between successive shafts 92. Each shaft 92 carries one of a group of three single helical gears 94 disposed to mesh with a central pinion 95; and each shaft 92'- carries one of a group of three single helical gears 94 disposed to mesh with a central pinion 95'. Both pinions 95 and 95' are carried by a single drive shaft 96 which is free to float both axially and radially. The pinion shaft 96 is shown connected to a flexible coupling 91 of any standard or approved type through which the shaft is driven in a manner not to inter- 95 are of opposite hand from that of gears 94' and pinion 95', and since both pinions are free to shift axially, they automatically assume a position such' as to equalize the axial thrust reactions imposed by the two groups of gears. The helix angle of one pinion and its meshing gears is preferably so related to that of the other pinion and its meshing gears that the power transmitted.

through the pinion shaft 96 is equally divided, an equal one half part being transmitted through each pinion 95 or 95' to the group, of gears 94 or 94' with which itmeshes; Consequently, one half of the power transmitted through the drive 5 shaft 96 is thus transmitted to each of the shafts 84 and 85.

Also, since the pinions 95 and 95' are free to shift radially, they automatically assume a position such that the total load transmitted through each is equally divided between the individual pinions 94 and 94' of each group, and each of the pinions 9| or 9I' transmits its proportional part of the torque load to the gear 88 or 9!] with which it meshes.

The gear set shown in Fig. 4 like those hereinabove described includes two coaxial, counterrotating, driven shafts I04 and I05, shaft I04 carrying an internal gear I08 and shaft I05 carrying an external gear I I9. Gear I08 is driven by three equally spaced pinions I I I, each carried by a shaft H2 suitably journalled in the housing I01 and driven by a gear I I4 carried thereby. Likewise, gear H is driven by three equally spaced pinions III each carried by a shaft H2 driven by a gear H4 thereon. The three gears II 4 of one group mesh with a centrally disposed driving pinion I I and the three gears I I4 of the other group mesh with a separate similarly disposed driving pinion I I5.

Also, as in the form of gear set shown particularly in Fig. 3, the two driving pinions H5 and I I5 are free to float radially, so as to equally distribute the torque load transmitted through each to the three gears H4 or H4 with which they mesh, and so that the three pinions I I I transmit substantially equal torques to the gear I08 and the three pinions III transmit substantially equal torques to the gear Hi). As distinguished from the Fig. 3 arrangement, however, the total torque transmitted to one gear I08 in the Fig. 4: arrangement bears no definite relation to the total torque transmitted to the other gear I ll], so that each shaft I04 and I95 is positively driven, regardless of the presence or absence of torque load on the other shaft.

For this purpose the two driving pinions H5 and H5 are shown separately driven through suitable connectors H6 and H6 from a suitable flexible coupling III. In this instance each connector is shown as a tubular structure having toothed driving engagement, as at H8 or H8, with the coupling H1 and also similar engagement at H9 or I I9 with its associated pinion H5 or H5.

In the gear set of Fig. 4 the several gears and pinions are shown as of double-helical type, the several shafts H2 and H2 being free to float axially to permit the pinions II I and III to accommodate themselves to the gears I08 and H0, respectively; and the two driving pinions I I5 and H5 are also free to float axially for a like purpose.

Various changes may be made in any of the embodiments of the invention hereinabove speciflcally described without departing from or sacrificing the advantages of the invention as defined in the appended claims.

I claim:

1. In a gear set for driving two driven shafts from a single driver, said gear set comprising a pair of gears connected in driving relation with said driven shafts respectively, a group of gears each separately connected in driving relation with one of said 'pair of gears, a second group of gears each separately connected in driving relation with the other of said pair of gears, and means driven by said driver for simultaneously driving both of said groups of gears, said last named means including pinions engaged with said groups of gears and reacting thereon to distribute between the gears of each group the torque load imposed upon the gear to which said group of gears is connected.

2. In a gear set for driving two coaxial counterrotating shafts from a single driver, said gear set comprising a pair of coaxial gears connected in driving relation with said shafts respectively, a group of gears each separately connected with one of said coaxial gears to drive the latter in one direction, a second group of gears each separately connected to the other of said coaxial gears to drive the latter in the opposite direction, and means driven by said driver for driving both of said groups of gears, said last named means including pinions engaged with said groups of gears and reacting thereon to distribute between the gears of each group the torque load imposed upon the gear to which said group of gears is connected.

3. In a gear set for driving two coaxial counterrotating shafts from a single driver, said gear set comprising an internal gear for driving one of said shafts, an external gear for driving the other of said shafts, a group of gears each separately connected with said internal gear to drive the same in one direction, a second group of gears each separately connected with said external gear to drive the same in the opposite direction, and means driven by said driver for simultaneously driving both of said groups of gears, said means including pinions respectively engaged with said groups of gears.

4. In a gear set for driving two coaxial counterrotating shafts from a single driver, said gear set comprising an internal gear for driving one of said shafts, an external gear for driving the other of said shafts, a circular group of pinions each meshing with said internal gear, a second circular group of pinions each meshing with said external gear, two groups of gears, each of the gears of each group being separately connected in driving relation with one of said pinions, a pinion meshing with the gears of one of said groups, a second pinion meshing with the gears of the other group, and means driven by said driver for simultaneously driving said last named pinions.

5. In a gear set for driving two coaxial counterrotating shafts from a single driver, said gear set comprising an internal gear for driving one of said shafts, an external gear for driving the other of said shafts, a circular group of pinions each meshing with said internal gear, a second circular group of pinions each meshing with said external gear, two groups of gears, each of the gears of each group being separately connected with one of said pinions, a driving pinion engaged with the gears of one group and radially yieldable to substantially equalize the torque reactions therebetween, a second driving pinion engaged with the gears of the other group and radially yieldable to substantially equalize the torque reactions therebetween, and means through which said driving pinions are simultaneously driven by said driver.

WALTER. P. SCHMITTER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,740,756 Weiss Dec. 24, 1929 1,949,643 Banan Mar. 6, 1934 2,372,883 Daub Apr. 3, 1945 

